Climate Change and Corn a Bad Combo in Africa

Corn was thought to be more resistant to rising temperatures than other crops. But results from crop trials in Africa suggest that climate change could hurt corn (Zea mays) production.

Warmer temperatures and drought could be the one-two punch that knocks out corn harvests, warn David Lobell of Stanford University and researchers at the International Maize and Wheat Improvement Center.

“Projections of climate change impacts on food production have been hampered by not knowing exactly how crops fair when it gets hot,” Lobell said in a Stanford press release. “This study helps to clear that issue up, at least for one important crop.”

A modest one degree Celsius (1.8 degrees Fahrenheit) rise in temperature could result in a loss of harvest for 65 percent of Africa’s corn growing regions. If drought hits as well, all of the African corn belt will suffer some loss with 75 percent of the region losing as much as 20 percent of their harvest.

The warning comes after observations of 20,000 corn trials in Sub-Saharan Africa were compared to weather data collected from the same areas.

Results from the study will be published soon in the inaugural issue of Nature Climate Change.

“Essentially, the longer a maize crop is exposed to temperatures above 30 Celsius, or 86 Fahrenheit, the more the yield declines,” said co-author of the study Marianne Banziger of the International Maize and Wheat Improvement Center in the same press release.

“The effect is even larger if drought and heat come together, which is expected to happen more frequently with climate change in Africa, Asia, or Central America, and will pose an added challenge to meeting the increasing demand for staple crops on our planet,” Banzinger said.

This understanding of climate’s effect on corn in Africa actually came about serendipitously from two separate studies.

Farmers, agronomists, and other researchers had been carrying out studies to see what corn varieties did well in Africa.

“These trials were organized for completely different purposes than studying the effect of climate change on the crops,” Lobell said. “They had a much shorter term goal, which was to get the overall best-performing strains into the hands of farmers growing maize under a broad range of conditions.”

At the same time various organizations were collecting weather data over many years to establish climate patterns. The climate data collection was organized by the World Meteorological Organization.

Lobell put the climate data from various regions together with the crop yield information from the same areas.

“It was like sending two friends on a blind date – we weren’t sure how it would go, but they really hit it off,” Lobell said.

“I think we may just be scratching the surface of what can be achieved by combining existing knowledge and data from the climate and agriculture communities,” Lobell said. “Hopefully this will help catalyze some more effort in this area.”

Understanding how climate change will impact crop yields in the tropical regions is vitally important, because those regions will experience some the the strongest effects of rising global temperatures.

At the same time the tropics also have the fastest growing populations, and some of the highest rates of poverty. The possible combination of less food and more people creates a serious need to understand tropical agriculture in the face of climate change.

IMAGE 1: A field of corn grows on abandoned rail track at Gulu, Uganda, September 2010. (Wikimedia Commons)